1. Field of Invention
The present invention relates to a method for calculating an ocular distance, and more particularly to a method for calculating an ocular distance that is applicable to a three-dimensional (3D) image and thus to an interaction system.
2. Related Art
In recent years, applications of 3D images in the entertainment industry are developed rapidly, and all kinds of 3D image technologies have been gradually introduced into lives of ordinary people.
The imaging principle of the 3D image is that, the left eye and the right eye capture two images, and the brain synthesizes the two different images into a 3D image with a front to back depth of field.
Generally, the 3D image technology can be divided into a spectacle technology and a naked-eye technology. In the spectacle technology, a user needs to wear specially made spectacles to perceive different images with the left eye and the right eye through different light polarization angles or by shutter switching. In the naked-eye technology, the user can view 3D images on a screen without wearing spectacles. It can be seen by comparing the two technologies that, the spectacle technology has a longer history, and the relevant technologies are more mature; while the naked-eye technology is more convenient, but requires a higher cost.
The 3D images are also applicable to an interaction system. A user may interact with the 3D images through body movement. However, the user's perception for the position and the depth of field of the 3D images changes with the position of the user's eyes and the ocular distance. Therefore, when different users intend to use this interaction system, the ocular distances of the users must be calculated first to accurately reflect the users' real perception for the position and the depth of field of the 3D images.